The subject matter disclosed herein relates generally to isotope production systems, and more particularly to target windows for isotope production systems.
Radioisotopes (also called radionuclides) have applications in medical therapy, imaging, and research, as well as other applications that are not medically related. Systems that produce radioisotopes typically include a particle accelerator, such as a cyclotron, that has a magnet yoke that surrounds an acceleration chamber. Electrical and magnetic fields may be generated within the acceleration chamber to accelerate and guide charged particles along a spiral-like orbit between the poles. To produce the radioisotopes, the cyclotron forms a beam of the charged particles and directs the particle beam out of the acceleration chamber and toward a target system having a target material (also referred to as a starting material). The particle beam is incident upon the target material thereby generating radioisotopes.
In these isotope production systems, such as a Positron Emission Tomography (PET) cyclotron, a target window is provided between a high energy particle entrance side and a target material side of the target system. The target window needs to be capable of withstanding rupture under conditions of high pressure and high temperature. Conventional systems typically use a Havar foil to form this window. However, Havar foil activates with long lived radioactive isotopes. For certain target types, especially water targets, the target media is in direct contact with the foil and the long lived radioactive isotopes are transferred to the target media. The target media is normally processed before injection to a patient that removes the isotopes, but in some applications the isotopes will be injected in the patient, which can be harmful to the patient.